Quiz | Structure and Reactivity

1

Which compound is most acidic?

FCH2CO2H

ClCH2CO2H

BrCH2CO2H

ICH2CO2H

When comparing the acidity of different molecules, it is actually easier to compare the stability of their respective bases ⇒ less stable base = strongest base ⇒ strongest base = weakest acid

The more electronegative an atom, the stronger the inductive attracting effect and the more stable the base
Electronegativity: F > Cl > Br > I

 

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2

Which compound is most basic?

(CH3)3C​​​​​​​-

CH3CHCH​​​​​​​-

(CH3)2CCH​​​​​​​-

CH3CC​​​​​​​-

Lone pairs of electrons are stabilized by the s character of orbital. The % of s character is 25% in sp3 hybridization, 33% in sp2 and 50% in sp. Therefore, increasing basicity correlates with hybridization as follows: sp < sp2 < sp3​​​​​​​

 

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3

Which compound is an ether?

CH3CH2CH2COH

CH3CH2CH2COOH

CH3CH2OCH2CH3

CH3CH2COCH3

CH3CH2CH2COH ⇒ aldehyde;   CH3CH2CH2COOH ⇒ carboxylic acid;   CH3CH2OCH2CH⇒ ether;   CH3CH2COCH3​​​​​​​ ⇒ ketone

4

What is the correct IUPAC name of (CH3)2CHCH2CH(CH2CH2CH3)2?

1,1-dimethyl-3,3-dipropylpropane

1-isopropyl-2-propylpentane

2-methyl-4-propylheptane

6-methyl-4-propylheptane

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1) Longest chain: 7 carbon atoms ⇒ heptane
2) 1 methyl substituent + 1 propyl substituent
3) The left end is the closest to a subst.: number the C atoms from the left to the right
4) 2-methyl-4-propylheptane

5

Which of the following compounds is a Lewis Base?

BH3

H2O

AlCl3

All of the above

A Lewis base is a substance that donates an electron pair: H2O has 2 pairs of electrons on oxygen ⇒ it is a Lewis base
A Lewis acid is a substance that accepts an electron pair: BH3 and AlCl3 are electron-poor species (boron and aluminium need electrons to follow the octet rule) ⇒ BH3 and AlCl3 are Lewis acids

6

Which of the following cannot react as a nucleophile?

CH3OCH3

CH3OH

CH3O+H2

CH3OCH3

CH3O+H2 is an electrophile: electron-poor species that can form a covalent bond by accepting an electron pair from a nucleophile. Indeed the oxygen atom is positively charged and therefore poor in electrons